Brake rigging



Jul!!! 19, 1934. B. H. BROWALL 1,963,224

BRAKE RIGGING Filed Oct. 15. .1930 3 Sheets-Sheet 1 BRAKE RIGGING Filed Oct. 15. 1930 3 Sheets-Sheet 2 B Bran a June 19, 1934. B. H. BROWALL 1,963,224

BRAKE RIGGING Patented June 19, 1934 7 BRAKE RIGIG ING, Bert Henry Browall, Mal mo, Sweden, assignor' to svenska Aktieholaget"gronisregulator; Malmo, Sweden, a corporation of Sw'eden Appearances: 1 2. .6; is ria iN 4.8812 6! In- Sweden December-3, 192,9

reclaims.- 01; 188-195 My present invention refers'to'irnprovements in brake riggings for railway carsand the like. provided with means for variation of the lever- P age of the rigging in conformity with the load-on the car.

In railway cars and the like, and for the purpose of adapting the maximal braking-power according to the load on each separatecan-it-has previously been proposed tohave resort to a brake 1.0 rigging provided with means for variation of the leverage, so that it will be possible, for instance by manipulation of a handle bar or its-equivalent, to reverse the brake rigging from'a smaller leverage adapted for the braking of an empty car 2.130 a greater leverage adapted for the braking of a loaded car, or vice versa, and the present invention refers to improvements in brake riggings of this type.

On account ofthe depression ofthe car'sp'rings' Q due to the weightcf the load, it is practicallyime possible to prevent the distance between the brake shoes and the wheels from varying when unloading-the car,- or at the loading of an empty car,

i. etheoccasions at which a variation of therigging leverage takes place in practice; and the previously known arrangements for such purpose sufier from the disadvantage, that the intended variation of the leverage, in spite of the manipu-' lation of control means adapted therefor, is not 9 obtained when the slack between the brake shoes and the wheels is smaller than normal, as will be presently explained in the following; The main objectof the invention is to eliminate this disadvantage. The invention is illustrated in the accompanyin'g drawings, wherein Fig. 1 is a plan view of a known arrangement forfvariation of the leverage set "forth for a comcial measures; When'the brake is released,- -the parison with the-present, invention. V

Fig.- 2 -is an elevation showing a brake rigging constructed according togthe invention; and

Fig. 3-isa plan view of thesame.

Fig; 4;in a larger scale, showsaverticalsection of' the .apparatus-forvariation of the leverage,-

Fig; s-i -wplan' view of the latter; and

Fig 6;isa diagrammatic plan view-of a slightly modified form; the :brake'rigging being shown inplan'with'rthe wheels and adjacent parts of said sinsrine evation 9t E s hQYl r n:Q. l1?I d ver i sect ona deil. tame ififi o mhe parat for a s ation of the leverage, and

Figl Sis a plan-view of the arrangement shown in Fig '7'.

In the known -arrangenii mt accordingtoFig. 1,

the reference. a represents th'e brake cylinderproe vided with a piston. rod byadapted to be'actuatedby the piston (not shown); within'thei cylinder and to be moved tojtheleft inthefigurewhen braking. .The piston rodis connected-with'one-fiQw end'of. a brake lever c which'at its-other end isconnected with apull rod d adaptedjto transmit the braking power to the. shoes in a'knownmanner, and at apoint intermediate its ends therlever cis connectedzwith one end of a; pullrod-e; thei other end of which is connectedwith aflxedpointr in'the .car frame-4f nojother means-were. athand; the lever, 0, when braking; wouldtumr around the pivotal centre in the'pull rod s and thereby it would act with a certainleverager In: 0, the present'case this leverage can be assumed';to; be the greatest one, and it willcause a braking effect corresponding to a loadedcar;

Ifwthe leverage is 'to ,be varied; the "brakedever 0 must be given another; pivotal-centre'. :and- -ir r-y75 the" known arrangement according to- Fig; 1'? this is' obtained by turning of a cam disc-g, which then" comes into contact with a-guide-block-h,pivotdly' connected withthelever c. Thereby theylever will be caused to turn around the pivotal centre: 7

general condition that the brakeapiston; and

consequently also the piston rod b; when brakifii ing; shall always have a predetermined length of: stroke, and with regardhefeto the known -de-;."' vice described above cannot be used withoutispjez" slack between the brake. shoes and the wheelsfi'vg is not'influenc'ed in case the cam disog is'broiight into'oneof its positions orthe other; but when braking; aconsiderably 'sinalle'r length ofrstmkea. of-theupiston rod is obviously required for press;

ingzthebrake shoes in contact with :the wheeler 109 when the-lever c turnsaround'the' pivotal centre i (the a smaller leverage) thanwhenitzturns around'the pin j (the-greater'leverage) Consequent he le t of st oke fy he bra sems m st. e subjected t a va ation rnrer e ariatieaqf hlevere z e it i rinos i z e; ev it mea er @9 5 satisfy, the conditio x t Chit, regard tothe ons'tant lengthotstr oke spok en o at empt has bees we above mentioned variation of the brake piston stroke by positioning the cam disc g at a certain distance from the guide block h, thus, the cam disc g even when set into operation, will not touch the guide block it so long as the brake is released. At the initiating of a braking process, the leverflc will then atfirst turn around the pin f, whereby the guide block it is advanced towards the cam disc The distance between the guide block 72 and the cam disc g is of such a dimension that thecontact between the said parts takes place immediately before the brake shoes, at the turning of the lever 0 around the. pin 1, should have been brought, into contact with the wheels. In such case the brake piston would thus have travelled almost its entire normal length of stroke before the pivotal centre of the lever c, by the contact between the guide block h and the cam disc g, has been shifted over to the pin i. Thereby the very last part of the brake piston stroke only will be. influenced by thechange of the pivotal centre of the lever c,

and thus the piston stroke will very nearly have attained its normal value when the shifting of the fulcrum occurs. In this manner the difference in the length of the brake piston stroke will be so-small that it may be considered'tolerable.

Nevertheless, this construction involves, how-- ever, a serious drawback-It is obvious that in case the slack from one reason or another, for

instance the reasons hinted'at above, has become too small, the "brake shoes will go into contact with the wheels before the brake piston has travelled its normal length of stroke, when hormal.'It will be apparent that such an action braking. Consequently, the continued turning.

movement of the lever 0 will be prevented before the members 9 and it have come into contact with each other, and then the brake rigging will r continue in braking around the pivotal centre 1, in spite of the fact that the cam disc 9 has been adjusted so that its contact with. the guide block would have been secured, for the purpose of shifting of thepivotal centre, in case the slack between: the brake shoes and the wheels had been is positively intolerable.in practice, as the functionxofthe entire construction would be doubtful anduncontrollable.

It has been found that the mistake in previous m honstructions is that the support in the pin f is not positively removed from the lever c simultaneously with'the'provision of the new support for the same by meansof'the members 9! and h. The support'pffered by the pin' being still at hand itis :dependent on the greater or smaller length of stroke of thebrake piston at each application of" the brake whether the construction shall function in the desired manner ornot.

The'present .invention eliminates the drawback 'referred to in the foregoing, and generally it -'is characterized in that both of the two supporting points or pivotal centres for the brake lever (or all of-such points or centres,.incase more than two of them are employed, for inistancecif the leverage and braking power .re-

spectively is 'to be adjusted also for a partially loaded car) are reversible in such a manner that one' of' them'i's positively brought into" action simultaneously as the other is equally positively 7o brought out of action. 1 In practice the said supporting points are preferably interconnected 'in such a manner that the reversalof both, or all,

of them isfperformed simultaneously and with w I, one and-the same'manipulation, so that it'is im possible, for instance-due to carelessnesato put one of the supporting means or pivotal centres out of action without simultaneously putting another of them into action.

In the embodiment of invention illustrated in Figs. 2 and 3, the invention is shown applied to a brake rigging of a somewhat, modified form, in that the brake lever connected with the piston rod is constructed as a one-armed lever only. It ought to be evident to anyone, however, that the. circumstance, Whether the lever is con- 'structed with one or two arms, is without influence on the invention, as entirely in the same manner and by using exactly the same 'mechanical means it will be possible to shift the pivotal centres either at one end of the lever or at a point between the ends of the same.

- Referring to Figs. 2 and 3, the reference 1 represents the brake cylinder, and 2 is the brake lever connected with the piston rod 3, the said brake lever 2 corresponding to the lever c in Fig. 1. At a suitable point between its ends, the brake lever 2 is hingedly connected with a pull rod 4. At its other end, the brake lever 2 is adapted to be supported at either of the rigid supporting points 6 or '7, and by shifting over the support to one or the other of these points, the leverage will be varied in the same manner as described above. The means for transmitting the braking power by means of the pull rod 4 tothe brake shoes is also shown in the Figures 2 and 3, but since such means is beyond the scope of this invention, it seems superfiuous specifically to. explain the same in this connection. The apparatus for shifting of the supporting points has the general reference 8 in Fig. 3,.and the particulars of the same are shown in the Figs. 4 and 5.

From Fig.5 it is to be seen that the supporting points for the brake lever consist of pivot pins 7 6 and? respectively,'such pins establishing a pivotal connection between the lever and each. of

two longitudinally slidable plunger bars 9 and 10, the connection between the=pin 7 and the 1 plunger 10 being effected by meansof an intermediate link 11 for the purposeof permitting a rectilinear positive displacement of both of the plungers without tendency of jamming in their guides at the movement of the brake lever 2. Naturally, this link connection could also have they are rectilinearly guided by suitable means I acting in an equivalent variable in many difierent ways. Transversely of the direction of displacement of the plungers 9-and '10, and beyond the ends of the same. is rotatably mounted a shaft 12 rigidlyconne'cted with two lugs or cams 13 and 14 positioned in line with each of the plungers, such cams forming abutments radially extending from-' the shaft, and when they are two in number, they a're' prefer itself in the drawings but intended'to be connected with the crank 12 the shaft '12 may be turned ably positioned at an angular-distance of 90. -By

a suitable control mechanism which is not'shown 1411 a quarter of-airevolution, and thereby one or-the .5

other of the two cams may be brought-into action in opposition tothecorresponding plunger end, but simultaneouslyas one ofthe-cams is-brought into action, the other one is automaticallyand positively brought out of such position, and Hereby the support for the plunger not intended to be' usedis eifectively removed. I

In order, when the brake is released, to keep both of the plungers as far as possible away from the shaft 12, one of the plungers, for instance the plunger 9, is acted upon by a spring 15 mounted on the plunger 9 between acollar 22 secured to the said plunger and a disk 23 slidable thereon. In the position shown in Fig. 5 the disk 23 abuts a sleeve 24 screwed on the end of the plunger 9 and sliding in a socket 25 secured to the framing 21, but when the plunger 9 is moved to the right in Fig. 5 the disk 23 abuts the said socket 25. EW- dentlythis spring serves also the purpose of keeping the otherplunger 10 away from the shaft in a corresponding manner. A collar 16 on the other plunger 10 prevents the plungers from being pushed out from their guides.It is obvious that the spring to the same eifect may also be mounted for acting upon the other plunger 10, but then it will be subjected to a greater amountof compression. The main object of the means last described is that the ends of the plungers, when the brake is released, shall not take such an inner position that they are in the path of movement of either of the cams 13 or 14, as thereby they would be able to prevent a reversal of the cams.

In order that the cams, at the reversal, shall not be able to take any intermediate position, the shaft 12, in an angular position between the cams, is provided with a crank member 17 hingedly connected with a rod 18, which is longitudinally slidable in and guided by a guide means 19 suitably mounted turnably around a pin 19 so as to be able to take a position in correspondence with the different inclinations of the rod 18. By means of a coil spring 20 mounted around the rod 18, the crank member 17 is acted upon in such a manner that it must pass its dead centre in one direction or the other, and thereby it will prevent the cams from taking a non-desirous intermediate position the rotation of the shaft 12 being limited in the position to which it is turned through the idle cam which for this purpose abuts the-adj acent flange of the channel-shaped framing 21. This means may naturally also be constructed in 'other suitable ways and may be adapted for'permitting more than two different cam positions, in case more than two cams, or supporting points, are used.

V In the positions of the members shown in Figs. 4 and 5, the cam 13 is in its acting position, the cam 14 being out of action. As the corresponding pin 6 or supporting point 'for'the brake lever is positioned nearest to the point of connection 5 of the pull rod 4., the greater leverage is thus em- ,ployed. If the cams are reversed, the cam 14 will be brought into action, the cam 13 being inoperative, and the supporting point for the brake lever 2 is then shifted over to the pin '7 so that the leverage is reduced.It is evident without further explanation that exactly the same arrangement may also be used for shifting of the supporting points between the ends of the brake lever for instance the lever c (Fig. 1) in respect of which the points of connection iand 1 may be arranged in exactly the same manner as the points 6 and '7 in Fig.3.

In Figs. 7 and 8 a slightly modified form of apparatus is shown. The only difference between this form and the form shown in Fig. 4 is that there is interposed between the plungers 9 and 10 a third plunger 10 and between the cams 13 and 14 a third cam 14 corresponding to the plunger 10*. Inasmuch as in this embodiment the shaft 12 is to be rotated into three different angular positions for bringing the three cam members into action the crank 17 of Figs. 4 and dis replaced by a suitably shaped disk 17 with whichthe spring pressed rod 18 cooperates to prevent .the shaft 12 from taking nondesirous intermediate positions between the three positions in which the cams successivelybecome operative, the rod 18 for this purpose being provided with a pivoted roller 18 engaging any one of the notches 17* .provided on the disk 17*. i

Finally it is to be noted, that the variable lever age must not by necessity be applied in connection with the brake lever c and Z'respectivelyconnected with the brake piston rod. To the same effectit may also be applied to any other suitable lever .used in the brake rigging, and naturally more than one lever in the same rigging may also be constructed for variable leverage, in case the'construction of the rigging should necessitate such an arrangement.

In'Fig. 6 there is disclosed a form-of the invention wherein more than one of the brake leversfor transmission of the braking power to the brake shoes are provided with means for alter ation of the leverage of the rigging. The brake for accomplishing the said variation of the lever-' age. Pull rods 1 and I extend from the levers G and G to the supporting rigging for the clasp brake shoes in turn adapted for coaction with the wheels. It will be understood that this embodirnent of invention is adaptable for very long cars supported at-each end by a four wheel bogie,

and the variable leverage at each end may -beadaptable according to the amount of load at the separate ends of the car. 1

What I claim and desire to secure by Patent is 1. In a brake rigging of the character described, a variable leverage brake lever adapted for transmission or" the braking power to the brake shoes, means for providing pivotalcentres for said brake lever at different points along the length thereof, one movable abutment means foreach pivotal Letters centre and adaptedto form a rigid supporting point for the same, means for putting each of said abutment meansinto action at will, and

means for positively and effectively putting the rest of the abutment means into an inoperative position.

2. In a brake rigging according to claim 1, the additional feature that the abutment means are interconnected in such a manner that when one of the abutment means is brought into activity, the rest of them are simultaneously and automatically brought into an inoperative position.

means being adapted to form a pivotal connection with the brake lever.

5. In a brake rigging according to claim 1, the

' additional features that the abutment means are adapted to coact with the brake by the intermediary of corresponding slidable plunger means one end of which is adapted to form a pivotal connection with the brake lever, and that the abutment means are positioned in the elongation of the opposite ends of the plungers and mounted rigidly on a commonshaft in angular relation around the axis of said shaft.

6. In a brake rigging of the character described, a plurality of variable leverage brake levers adapted for transmission of the braking power to the brake shoes, means for providing pivotal centres for each of said brake levers at different points along the length thereof, one -movable abutment means for each pivotal centre and adapted to form a rigid supporting point for the same, means for putting each of said abutment means into action at will, and means for positively putting the rest of the abutment means for each of the said levers into an inoperative position.

'7.v In ,a brake rigging of the character described, a variable leverage brake lever adapted for transmission of the braking power to the brake shoes, means for providing two different pivotal centres for said brake lever at separate points along the length of the same, two movable abutment means each corresponding to one of said pivotal centres and adapted to form a rigid supporting point for the same, means for putting one of the said abutment means into action at will, and means for simultaneously and automatically putting the other of them into an inoperative position, and vice versa.

8. In a brake rigging of the character described, a variable leverage brake lever adapted for transmission of the braking power to the brake shoes, two plunger means adapted at their one ends to form a pivotal connection with said brake lever at different points along the length of the same, one movable abutment means provided for each of the plungers and adapted to act as a removable stopping member in the path of movement of the opposite free end of the corresponding plunger, means for alternately putting one of said abutment means into action at will, and means for simultaneously and automatically putting the other of them intoan inoperative position, and vice versa.

9. In a brake rigging according to claim 8, the additional feature that the abutment means the additional feature that one of the plunger means is adapted to form a pivotal connection with the brake lever by the intermediary of a link connection.

11. In a brake rigging according to claim 8, the additional feature that the plungers are acted upon by means permanently tending to displace them in a direction away from the abutment means, stopping means being provided for limitation of such displacement.

12. In a brake rigging of the character described, a variable leverage brake lever adapted for transmission of the braking power to the brake shoes, a framing, two plunger means positioned substantially parallel with each other and mounted longitudinally slidable in said framing, means for pivotal connection between one end of each of said plungers and the brake lever at diiferent points along the length of the latter, a shaft mounted in the framing transversely to the plungers and beyond the ends thereof remote from the lever, two cammembers rigidly connected with the shaft and each positioned in the elongation of the free end of the correspond ing plunger and in an angular relation to each other around the axis of the shaft, means acting upon the shaft and adapted to prevent it from coming to rest in a position in which none of the cam members is in operative position, means acting upon the plungers and permanently tending to displace them in a direction away from the cams, and stopping means adapted for the limitation of such displacement.

13. In a brake rigging of the character described, a variable leverage brake lever partaking.

sponding thereto, and means interconnecting the.

said movable abutment means in such a manner that when any one of the abu ment means is moved into operative position all the other ones are moved into inoperative positions.

BERT HENRY BROWALL. 

